Periodic glitches with Arduino nano and Savox SB-2290

Hello! 

I am trying to use this library with an Arduino nano and a Savox SB-2290 servo. The problem is that once every few seconds, the servo has a "glitch".
Using this library https://www.arduino.cc/reference/en/libraries/pwmservo/, the glitch disappear.

Any idea how to debug this ?

Regards,
Radu S.